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In this study, the ability of threshold based wavelet denoising Least Square Support Vector Machine (LSSVM) and Artificial Neural Network (ANN) models were evaluated for forecasting daily Multi-Station (MS) streamflow of the Snoqualmie... more
In this study, the ability of threshold based wavelet denoising Least Square Support Vector Machine (LSSVM) and Artificial Neural Network (ANN) models were evaluated for forecasting daily Multi-Station (MS) streamflow of the Snoqualmie watershed. For this aim, at first step, outflow of the watershed was forecasted via ad hoc LSSVM and ANN models just by one station individually. Therefore, MS-LSSVM and MS-ANN were employed to use entire information of all sub-basins synchronously. Finally, the streamflow of sub-basins were denoised via wavelet based thresholding method, then the purified signals were imposed into the LSSVM and ANN models in a MS framework. The results showed the superiority of ANN to the LSSVM, MS model to the individual sub-basin model, using denoised data with regard to the noisy data, e.g., DCLSSVM=0.82, DCANN=0.85, DCMS-ANN=0.91, DCdenoised-MS-ANN=0.94.
Research Interests: Denoising and Stream Flow
Sloping ground near the footings have an adverse effect on their performance. Slope increases the settlements of the footings and while it reduces their bearing capacity. In the present paper, a footing with rough base has been considered... more
Sloping ground near the footings have an adverse effect on their performance. Slope increases the settlements of the footings and while it reduces their bearing capacity. In the present paper, a footing with rough base has been considered for the analysis. The bearing capacity factors have been determined with the consideration of resistance of soil above the foundation level. A simple limit equilibrium method has been used to evaluate bearing capacity. The parameters considered for the analysis include the distance between edge of slope and center of footing, slope angle and foundation depth. It is observed from the analysis that bearing capacity reduces as distance between footing and the edge of the slope decreases. Increase in slope angle cause the reduction in the bearing capacity.
Research Interests:
Having so many old and burnout hospitals in third world countries is one of the major problems in the health sector. This issue besides low per capital hospital beds has led to many problems in the health department. In big cities, the... more
Having so many old and burnout hospitals in third world countries is one of the major problems in the health sector. This issue besides low per capital hospital beds has led to many problems in the health department. In big cities, the possibility to provide land for the construction of alternative hospitals is very costly and non-economic and even impossible. Considering the complexities of building a new hospital, the only solution is making reforms in the hospitals through renovation or rebuilding the project. Moreover, increased general inflation and currency fluctuations in third world countries make most hospitals and medical centres into trouble, which this issue results in increased medical costs. Thus, cost savings in hospitals have a significant impact on their workflow and consequently patient satisfaction in terms of quality of services. Lack of proper implementation of hospital spaces reform projects has challenged realization of these savings. Building Information Modelling (BIM) is revolutionizing how to design and implement buildings. Moreover, it is not just a 3D tool in CAD, but it is a kind of database, which makes possible providing a wide range of information about features and relations among various sections of a building. This study aims to evaluate the need to recognize and measure the reduction of duplications in the hospital spaces reform projects using BIM, in order to make significant savings in waste of hospitals’ resources. In-depth literature review method is applied to collect proper data aiming to introduce BIM as a tool to reduce costs of hospitals’ reforms. This study helps project stakeholders in the field of health infrastructure to better understand the importance of BIM application to prevent various financial wastes in the projects and fulfil their decisions with better recognition.
Research Interests:
Maximum shear wave velocity is one of the most important dynamic parameters of soils which contributes in estimating the dynamic behaviour of soils through the maximum shear modulus. There are different methods for measuring shear wave... more
Maximum shear wave velocity is one of the most important dynamic parameters of soils which contributes in estimating the dynamic behaviour of soils through the maximum shear modulus. There are different methods for measuring shear wave velocity either in laboratory or in the field. One of the laboratory methods that recently has become popular due to its simplicity, is use of Bender Elements in soil samples. Contrary to its simplicity, it has several uncertainties in its data interpretation. Frequency at which the shear wave velocity is measured is one of the effective parameters that significantly affects the clearance of received wave. This article presents results from a laboratory investigation into the shear wave velocity measurement of remolded specimens of Firoozkooh sand. Specimens were subjected to 13 different levels of frequency and 11 different levels of confining pressure. Results shows that by increasing the confining pressure, the frequency at which the received wave has the best clearance, increases. It also shows that frequency dependence of soils increases by increasing the confining pressure.
Research Interests:
The effects of firebreak in high-rise buildings seem essential to be investigated cautiously since world trade center towers incident. Consequently, many technological advancements were achieved and numerous researches were performed.... more
The effects of firebreak in high-rise buildings seem essential to be investigated cautiously since world trade center towers incident. Consequently, many technological advancements were achieved and numerous researches were performed. Nevertheless, in 2017, Plasco building in Iran also was set ablaze and the consequence was the full destruction of the building, claiming lives of at least 20, injuring 70 and loss of thousands of jobs. Therefore, it is crucial to investigate the effects of fire in high-rise buildings more thoroughly in order to prevent progressive collapse, a phenomenon that caused the destruction of the two landmarks. Ordinarily, to achieve this goal, methods of analysing fire effects are developed. So by choosing a logical fire scenario, design fire is extracted from time-temperature relations of design codes. After determining the firing temperature at various times, effects of temperature increase on the material's mechanical properties are investigated. Important characteristics such as concrete compressive strength, concrete and steel modules of elasticity, tensile strength, the coefficient of thermal expansion and steel rebar yielding stress are affected by alterations of temperature. Finally, by analysing structural behaviour utilizing modelling programs and comparing results of different fire temperatures and stories in which fire occurs with the initial design of the building RCC frame, it can be concluded that axial forces increases in columns are the critical condition in fire situations and in case of fire break in distinct stories, lower floors will experience a sharper surge of axial forces.
Research Interests:
Gypsum plaster is a widely used building material, as it is inexpensive and mechanically strong and to make gypsum model for ceramics manufacture as modelling material. When in contact with water, calcined gypsum rehydrates through... more
Gypsum plaster is a widely used building material, as it is inexpensive and mechanically strong and to make gypsum model for ceramics manufacture as modelling material. When in contact with water, calcined gypsum rehydrates through dissolution, nucleation and crystallization steps. In this work, the mixing rate of plaster with water was investigated on their effect on the properties of hardened gypsum pieces, focusing on the structure–function relationship. The mixing plaster with water was done at 120, 240, 360 and 600 rounds per minute with a constant water/ plaster ratio of 0.77. The results showed that with increasing mixing rate, the setting time decreased and the mechanical strength of the hardened piece increased. The apparent porosity, water absorption and water diffusion coefficient of the hardened piece decreased with increasing mixing rate. The microstructure of gypsum with the high mixing rate not only seems to be denser, with crystals interlaced, but also shows short crystals, which may improve the mechanical strength of the specimen. The higher mixing rate can lead to the higher rate of the nucleus formation, the smaller crystals and denser structure are formed. This material can have higher strength.
Research Interests:
Nowadays the proper sanitary disposal of waste is considered as one of the main options in waste management. The chemicals produced from landfills’ leachate affects the structure and characteristics of clay layers, so based on the... more
Nowadays the proper sanitary disposal of waste is considered as one of the main options in waste management. The chemicals produced from landfills’ leachate affects the structure and characteristics of clay layers, so based on the acidity/basicity state of leachate, the study of the geotechnical properties of clay layers under the influence of these materials is very important. Therefore, in this research, the effect of PH variation on the geotechnical parameters of the soil was investigated by conducting a series of Atterberg limits, permeability and consolidation experiments on kaolinite clay and kaolinite mixture with different percentages of bentonite. In these experiments, acetic acid and sodium hydroxide were used as chemical agents representing leachate. Permeability parameters were measured via falling head method. The results of experiments show that the presence of acid and base in the kaolinite clay and the kaolinite mixture with different percentages of bentonite increases the liquid limit, plastic limit and permeability of the soil, as well as increasing the level of settling and accelerating the consolidating process. Addition of 10% bentonite also enhances the liquid limit from 36 to 41 (13%), and the addition of further 10% bentonite enhances the liquid limit from 36 to 46 (27%) at pH=7. Soil settling increases 6% when exposed to acetic acid and 17% in light of exposure to sodium hydroxide in kaolinite Permeability index is enhanced 14% with the addition of acid and 25% with the addition of base in kaolinite. increasing of 10% in bentonite to the same sample of kaolinite soil reduces the permeability index from 21% and an addition of further 10% of bentonite, decreases the original permeability index from 1.42×10-7 to 0.61×10-7 at PH=7.
Research Interests:
Collapsible soils is one of the problematic soil because of complex mechanism collapse in them, the recognizing and analyzing effective parameters on phenomenon is so important. Collapsible soil is non-saturate soil, due to moisten and... more
Collapsible soils is one of the problematic soil because of complex mechanism collapse in them, the recognizing and analyzing effective parameters on phenomenon is so important. Collapsible soil is non-saturate soil, due to moisten and specifically loading, connection between soil particles become loose and finally suddenly destroying happen in soil layer. In this study, collapsible potential in soil layers of Hir city based on practical methods were evaluated. 16 specimens were collected in study area. Practical methods were divided to qualitative and quantitative criterions. In quantitative procedure, double odeometer test based on ASTM were performed. Results of this study showed that between qualitative methods there is not good agreement. Although, quantitative procedure proposed high risk in terms of collapsibility in soil layer.
Research Interests:
This paper presents the result of an experimental investigation on a full-scale reinforced lightweight aggregate embankment. The reinforced body was expanded clay aggregates, reinforced with geotextile facing. Loadings included... more
This paper presents the result of an experimental investigation on a full-scale reinforced lightweight aggregate embankment. The reinforced body was expanded clay aggregates, reinforced with geotextile facing. Loadings included self-weight, static surcharge applied using concrete slabs on top of the embankment, and dynamic loads simulated by a vibrator on top of the concrete slabs as well as dropping weight impacts. The system was designed using load and resistance factor design. Measured parameters included lateral and vertical deformations, velocity, and acceleration during tests. This paper covers design and construction details of the built embankment. Results indicate viability of using lightweight expanded clay aggregate in the proposed mechanically stabilized earth walls with geotextile facing as a mean for accelerated construction of bridge abutments.
Research Interests:
In this paper a numerical investigation of installation of actuator in a toggle configuration for decreasing of active control forces in engineering structures has been carried out. During the past two decades, researchers have been... more
In this paper a numerical investigation of installation of actuator in a toggle configuration for decreasing of active control forces in engineering structures has been carried out. During the past two decades, researchers have been focused to prevent the vibration of tall building from strong earthquakes. For achieving this purpose, they applied either massive conventional bracing or passive energy dissipation dampers. Subsequently, they developed active control systems in structures to resist against the high seismic loads. However, this later method eventuates installing massive actuators in building which are not only very costly and uneconomically but also needs large electricity power. In this research, using by known earthquakes, investigation of the effects of the toggle configuration on actuator forces has been performed numerically. For numerical investigation, active tendon control system was selected as a comparison. The numerical investigation shows significant reduction in actuator forces through using toggle configuration. Finally, comparing results through the numerical processe express high matching that relies on mitigation of control forces in the toggled active model.
Research Interests:
Shear modulus and confined modulus are important parameters for static and dynamic analysis in geotechnical applications. Cyclic simple shear apparatus had been developed by mounting bender element and ultrasonic sensors to measure... more
Shear modulus and confined modulus are important parameters for static and dynamic analysis in geotechnical applications. Cyclic simple shear apparatus had been developed by mounting bender element and ultrasonic sensors to measure continuous shear wave and pressure wave velocities for determination of Gmax and M. For this purpose two new pedestals have been fabricated on which HAE ceramic disc and sensors were mounted. A pressure control panel and a hanging column system have been designed to apply high and low matric suction values with high accuracy. Finally, some tests was conducted to verify the result of device performance and to compare with the theoretical results of unsaturated soils.
Research Interests:
In this experimental study, the mechanical strength properties of concrete using 5, 8 and 12% of organic waste ash (OWA) instead of cement are investigated. The results showed that the 28 days compressive and tensile strength and slump of... more
In this experimental study, the mechanical strength properties of concrete using 5, 8 and 12% of organic waste ash (OWA) instead of cement are investigated. The results showed that the 28 days compressive and tensile strength and slump of the concrete made by OWA in compared with ordinary concrete were 0.99, 0.99, and 0.8, respectively, for 5% OWA instead of cement, 0.96, 0.9, and 0.69, respectively, for 8% OWA instead of cement, and 0.9, 0.9, and 0.09, respectively, for 12% OWA instead of cement.
Research Interests:
Semi active devices can be used to control the responses of a continuous bridge during earthquake excitation. They are capable of offering the adaptability of active devices and stability and reliability of passive devices. This study... more
Semi active devices can be used to control the responses of a continuous bridge during earthquake excitation. They are capable of offering the adaptability of active devices and stability and reliability of passive devices. This study proposes two semi-active control method protection of bridge using variable stiffness and damping systems and MR dampers. The first method is variable stiffness and damping with eight different (on-off) control schemes which is optimized with genetic algorithm. Genetic algorithm is used to define the parameters of this method. In the second method, an intelligent controller using fuzzy control of MR damper is developed. In particular, a fuzzy logic controller is designed to determine the command voltage of MR dampers. In order to evaluate the effectiveness of the proposed method, the performances of the proposed controllers are compared in numerical study. Results reveal that the developed controllers can effectively control both displacement and acceleration responses of the continuous bridge.
Research Interests:
Autoregressive integrated moving average (ARIMA) models are appropriate for the annual streamflows (annual peak and maximum and also mean discharges) of the Karkheh River at Jelogir Majin station of Karkheh river basin in Khuzestan... more
Autoregressive integrated moving average (ARIMA) models are appropriate for the annual streamflows (annual peak and maximum and also mean discharges) of the Karkheh River at Jelogir Majin station of Karkheh river basin in Khuzestan province in western Iran, through the Box-Jenkins time series modelling approach. In this research among the suggested models interpreted from ACF and PACF, ARIMA(4,1,1) for all annual streamflows satisfied all tests and showed the best performance. The model forecasted streamflow for ten leading years showed the ability of the model to forecast statistical properties of the streamflow in short time in future. The SAS and SPSS softwares were used to implement of the models.
Research Interests:
In this paper the water cycle algorithm (WCA) is utilized for sizing optimization of space trusses. Finding the optimum design of 3-D structures is a difficult task as the great number of design variables and design constraints are... more
In this paper the water cycle algorithm (WCA) is utilized for sizing optimization of space trusses. Finding the optimum design of 3-D structures is a difficult task as the great number of design variables and design constraints are present in optimization of these type of structures. The efficiency of the WCA are demonstrated for truss structures subject to multiple loading conditions and constraints on member stresses and nodal displacement. Numerical results are compared with those reported in the literature where the obtained statistical results demonstrate the efficiency and robustness of WCA where it provided faster convergence rate as well as it found better global optimum solution compared to other metaheuristic algorithms.
Research Interests:
Indoor air quality is inevitably linked to ambient air quality. What controls ambient air quality also affects indoor air quality. The desert belts and their respective dust plumes on a global basis regulate ambient air quality. Each... more
Indoor air quality is inevitably linked to ambient air quality. What controls ambient air quality also affects indoor air quality. The desert belts and their respective dust plumes on a global basis regulate ambient air quality. Each desert has its own exclusive extension zone and during the period of cyclonic depressions millions of tons of dust is injected into the atmosphere. These dust particles having 10-micron size or less can traverse long distances and are composed of clay minerals and embedded bacteria fungus and viruses. It has been shown that when inhaled it may adversely affect the respiratory system as well as triggering genes that are responsible from the production of specific proteins that results with migraine attacks. Basing on this work we have developed simple water based air purifier system that can effectively removes 90 % of particles in an hour and ultimate purification is reached within 120 minutes in one cubic meter experimental chamber. Of course, increase in air flux will inevitably shorten the time necessary for ultimate purification for a given environment. The air purifying system consists of an aquarium pump hose and air stone and simple 5 l water bottle. The basic principle behind the purification system based on the fact that during the rise of air bubble the air bubbles increases the surface area that is in contact with water and friction with water creates a vortex further assisting the transfer of any particles and bacteria fungus and virus to water phase. With this simple purification system the adverse effect of dust particles can effectively be removed from indoor environment. Renewing the water is the only thing required for the continuation of effective purification. The water is not wasted and can be used to irrigate the flowers lawns etc. Such systems also offer an ideal low cost pre-cleaning filtering that can be used to extent the operational life of expensive filtering systems.
Research Interests:
Dynamic soil properties are very important topic in geotechnical earthquake engineering due to associated with dynamic loading. Probabilistic analysis of dynamic soil properties is as effective tools to evaluate uncertainty of soil... more
Dynamic soil properties are very important topic in geotechnical earthquake engineering due to associated with dynamic loading. Probabilistic analysis of dynamic soil properties is as effective tools to evaluate uncertainty of soil parameters. In this paper, Monte Carlo Simulation (MCS) is used for reliability assessment of dynamic soil properties. For this purpose, a famous model is selected for predicting normalized shear modulus reduction and damping ratio curves. The selected stochastic parameters are internal friction angle, dry and saturated unit weight of soil which is modeled using normal probability distribution functions. To assess the reliability of dynamic soil parameters a computer model is developed for generating input parameter uncertainties. The results show that the shear modulus and damping ratio have more uncertainty for middle range of shear strain. The sensitivity analysis's results show that saturated unit weight is the most effective parameter in shear modulus and damping ratio.
Research Interests:
In recent years, with the increasing demand for modern and environmentally friendly materials, natural pozzolan s can be proved to be such a material and several researchers have focused their research efforts in using it as a partial... more
In recent years, with the increasing demand for modern and environmentally friendly materials, natural pozzolan s can be proved to be such a material and several researchers have focused their research efforts in using it as a partial substitute in the manufacture of concrete and mortar. This study concerns the fresh and hardened properties of self-compacted concrete (SCC) with natural zeolite (NZ). SCC mixtures were prepared by inclusion various amounts of NZ (0-20% by weight of cement) at different water/binder ratios. The fresh properties were investigated by slump flow, visual stability index, T50, V-funnel and L-box. The slump flow and compressive strength changes with hauling time were also considered. The hardened properties were tested for compressive strength, splitting tensile strength, ultrasonic pulse velocity (UPV), initial and final absorption. Results showed that with the inclusion of NZ, SCC can be successfully produced with satisfactory performance in flow ability, passing ability and viscosity. For all mixtures, flowability was lost with hauling time, although the rate of slump flow reduction was higher for mixes with higher amount of NZ. Regarding to hardened properties, the effect of NZ on the compressive and splitting tensile strength of SCC mixtures is generally related to its W/B ratio. Moreover, compressive strength enhancement was seen for mixes with slump flow higher than 550 mm at prolonged mixing time. The UPV measurement shows that the effect of NZ on the UPV values at a high compressive strength are negligible. Compared to control SCC, absorption characteristics of SCC containing NZ significantly decrease with increasing ages.